What was found
(CAN) APPROXIMATELY 10 MINUTES FROM DESTINATION, AIRCRAFT DECLARED AN EMERGENCY DUE TO SMOKE IN THE LAVATORY. AIRCRAFT WAS DESCENDING THROUGH 5,000 FT WHEN THE BLEEDS WERE SWITCHED FROM ENGINES TO APU. WITHIN A SHORT PERIOD OF TIME A BURNT OIL SMELL WAS OBSERVED IN THE CABIN, AND THE LAV SMOKE DETECTOR WAS GOING OFF. THE CREW ALSO RECEIVED A "TOILET SMOKE" CAUTION MESSAGE. CREW REQUESTED EMERGENCY SERVICES BE ALERTED FOR ARRIVAL. SHORTLY THEREAFTER THE SMOKE INDICATION WENT OUT. FLIGHT LANDED SAFELY. MAINTENANCE INVESTIGATED AND FOUND THE APU OVER SERVICED. EXCESS OIL WAS DRAINED TO AN ACCEPTABLE LEVEL, AND LT & RT COALESCER BAGS P/N 753689-3 REPLACED IN ACCORDANCE WITH THE AMM 21-51. AIRCRAFT WAS THEN RUN ON A